High-pressure fuel pump systems are used in a variety of motorized platforms, including those of trucks, buses, and automobiles, as well as off-road machines utilized in construction, mining, and agricultural fields. They are also utilized in marine as well as industrial applications, the latter including, by way of example, electric power generation and petroleum drilling rigs. Such pumps are generally mechanically driven via associated engines for delivering fuel under high pressure to fuel injectors and into individual cylinders of the engines through so-called common rail fuel systems.
Common rail fuel systems generally include fuel delivery components associated with a high-pressure variable delivery pumps. A variable delivery pump may be effective to deliver high-pressure fuel into a manifold that acts as a central accumulator for the high-pressure fuel prior to its delivery to individual injectors. The manifold thus dampens pressure fluctuations occurring from discreet high pressure pumping events. Typically, the fuel is sourced from a fuel tank by means of a low pressure fuel transfer pump to the variable delivery high-pressure fuel pump.
Apart from atmospheric emissions control purposes, the fuel is pressurized to facilitate the accurately timed and controlled delivery of discrete fuel amounts to the fuel injectors. As such, an electronic control system is generally employed to monitor and optimize system fuel pressure. The electronic control system operates the high-pressure pump as well as each of the electronically actuated fuel injectors to optimize fuel pressure and quantity, as well as timing of delivery, under a variety of engine operating conditions.
Normally, such systems include capabilities for managing fluid dynamics and pressurization of the fuel pump manifold and or rails. As an example, high pressure valves can be used to manage fluid flow and pressure control. However, life of the valve seat is such high pressure valves is often limited due to relative motion and the high contact stress between the valve body and valve seat. The combination of high stress and motion results in adhesive wear which ultimately results in valve leakage. Improvements in valve operation are needed to maintain operable life of the components and minimize leakage.
As an example, U.S. Pat. No. 5,012,785 (the '785 patent) describes a valve operatively mounted in an axially extending center bore of a high pressure pump rotor. The valve axially shifts between an open position in which a charge of fuel generated by the pump is transmitted as a pressure wave to a fuel injector nozzle and a closed position in which the pump charging chamber is sealed from the injection line and the injection line is vented to low pressure so that secondary pressure waves reflecting from the injector nozzle will be routed to the low pressure line for dissipation therein rather than rebounding from the delivery valve. Although the injection line of the '785 patent is vented, such venting does not address valve motion control and minimizing wear between the valve body and the valve seat. These and other shortcomings of the prior art are address by this disclosure.